1. Field of the Invention
The present invention relates to an absorption cold or hot water generating machine, and more particularly to an absorption cold or hot water generating machine which is driven by an exhaust gas, can effectively utilize a high-temperature exhaust gas discharged from an external apparatus such as a gas turbine to increase exhaust heat utilization efficiency, and can be compact.
2. Description of the Related Art
In the case where an absorption cold or hot water generating machine is driven by a high-temperature exhaust gas having a temperature of about 200 to 400, when the absorption cold or hot water generating machine is operated for air cooling, it is known that the high-temperature exhaust gas is utilized in double effect, and is utilized in single effect when the temperature of the exhaust gas is lowered, thus increasing exhaust heat utilization efficiency. Such absorption cold or hot water generating machine has been proposed in Japanese patent publication No. 57-20543, Japanese laid-open patent publication No. 11-304274, and the like.
However, in the above conventional absorption cold or hot water generating machine, the circulation flow of absorption solution imposes restrictions on an arrangement of constituent equipment, and an exhaust gas path for allowing an exhaust gas serving as a heat source of a generator to pass therethrough and an absorption solution piping for allowing absorption solution to pass therethrough are complicated, and hence it is difficult for the absorption cold or hot water generating machine to be compact.
Further, in the above conventional absorption cold or hot water generating machine, because the absorption solution piping is extended in a complicated manner, and an exhaust heat recovery generator and a low-temperature generator have the same pressure, a pump must be separately provided or a potential head must be utilized to feed absorption solution. In the case of utilizing the potential head, the arrangement of constituent equipment is limited by a positional relationship, i.e. height relationship.
In order to construct the absorption cold or hot water generating machine into a compact unit, it is necessary to arrange the position of the upper surface of the exhaust heat recovery generator at a height equal to or lower than the height of a low-temperature shell or casing comprising an absorber, an evaporator, a low-temperature generator and a condenser.
In the absorption cold or hot water generating machine disclosed in the Japanese laid-open patent publication No. 11-304274, an exhaust heat recovery generator is provided at a position higher than a low-temperature shell comprising an absorber, an evaporator, a low-temperature generator and a condenser to facilitate circulation of solution. However, such absorption cold or hot water generating machine has a disadvantage that the absorption cold or hot water generating machine has a large height and is not compact.
Further, in the absorption cold or hot water generating machine disclosed in the Japanese laid-open patent publication No. 11-304274, it is necessary to provide a pump separately to feed absorption solution from an exhaust heat recovery generator or a low-temperature generator to a high-temperature generator having a higher pressure.
The specific volume of the high-temperature exhaust gas serving as a heat source is very large, and a volume flow rate of the high-temperature exhaust gas becomes large. In the case where the high-temperature exhaust gas is led at a large volume flow rate to the high-temperature generator, and then the exhaust heat recovery generator, a large installation volume is required to provide an exhaust gas path depending on the manner in which the exhaust heat recovery generator is arranged.
In the absorption cold or hot water generating machine disclosed in the Japanese patent publication No. 57-20543, if an exhaust gas path is extended in a complicated manner, it is difficult to make the absorption cold or hot water generating machine compact.
Further, gas-liquid separation in the exhaust heat recovery generator generally requires a large volume, and hence the dimension of a gas-liquid separator becomes a bar to provide the exhaust gas path.
The present invention has been made in view of the above drawbacks in the prior art, and it is therefore a first object of the present invention to provide an absorption cold or hot water generating machine which is driven by an exhaust gas, can effectively utilize a high-temperature exhaust gas by a simple apparatus structure, and has a high thermal efficiency.
A second object of the present invention is to provide an absorption cold or hot water generating machine which is driven by an exhaust gas, and can be compact in an overall structure by improving connecting relationship of constituent equipment within a cycle.
In order to achieve the first object, according to a first aspect of the present invention, there is provided an absorption cold or hot water generating machine comprising: an absorber; a low-temperature generator; an exhaust heat recovery generator; a high-temperature generator; a condenser; an evaporator; a solution path and a refrigerant path for connecting the absorber, the low-temperature generator, the exhaust heat recovery generator, the high-temperature generator, the condenser, and the evaporator; and an exhaust gas path for introducing a high-temperature exhaust gas serving as a heat source into the high-temperature generator, and then the exhaust heat recovery generator; wherein the low-temperature generator comprises a liquid film-type generator in which solution is sprayed on a heat transfer tube bank, and the refrigerant vapor generated in the exhaust heat recovery generator is led to the heat transfer tube bank of the low-temperature generator.
In the absorption cold or hot water generating machine, the absorption solution heated and concentrated in the low-temperature generator by the refrigerant vapor supplied from the high-temperature generator should be led to the exhaust heat recovery generator. Further, in the exhaust gas path of the high-temperature exhaust gas in the high-temperature generator, a burner for combusting fuel supplied from the outside should be provided to cope with the shortage of cold or hot water capacity.
In the absorption cold or hot water generating machine which utilizes the high-temperature exhaust gas, in order to utilize the quantity of heat of the exhaust gas as much as possible as a heat source of the high-temperature generator for thereby increasing thermal efficiency, it is necessary to lower the temperature in the high-temperature generator.
According to the present invention, in order to lower the condensation temperature of the refrigerant vapor supplied from the high-temperature generator for thereby lowering the boiling temperature in the high-temperature generator, the heat transfer of the low-temperature generator is improved for thereby lowering the boiling temperature.
The low-temperature generator comprises a liquid film-type generator for spraying solution on the heat transfer tube bank to increase the heat transfer, and the rise of boiling pressure and boiling temperature which may be caused by the liquid level in the case of a flooded-type generator can be prevented.
Further, a condenser may be provided for each of the low-temperature generator and the exhaust heat recovery generator. However, in the present invention, a single condenser is used for both the low-temperature generator and the exhaust heat recovery generator to make an overall apparatus compact. Further, the refrigerant vapor (in some cases refrigerant vapor contains droplets of solution) is led to the tube bank of the low-temperature generator, and both of the low-temperature generator and the exhaust heat recovery generator share gas-liquid separation to make the overall apparatus compact and reduce the cost of the apparatus.
Further, solution having a lower concentration than solution in the exhaust heat recovery generator is introduced into the low-temperature generator, and is then led to the exhaust heat recovery generator. Specifically, the concentration of solution in the low-temperature generator is lowered to reduce the boiling temperature, and the condensation temperature of the refrigerant vapor supplied from the high-temperature generator and serving as a heat source is lowered. Incidentally, if the quantity of exhaust heat is small, the quantity of heat may be supplemented by a burner or the like.
The absorption cold or hot water generating machine may further comprise a combustion device provided in the exhaust gas path for combusting fuel supplied from the outside. The combustion device may comprise a burner.
The absorption solution heated and concentrated by the refrigerant vapor supplied from the high-temperature generator in the low-temperature generator may be led to the exhaust heat recovery generator.
The solution path may include a path for allowing a diluted solution flowing from the absorber to be branched and to flow to the high-temperature generator and the exhaust heat recovery generator, and a path for allowing the solution heated and concentrated in the high-temperature generator to flow from the high-temperature generator to the low-temperature generator.
The solution path may include a path for allowing a diluted solution flowing from the absorber to be branched and to flow to the low-temperature generator and the exhaust heat recovery generator via a low-temperature heat exchanger, and to the high-temperature generator via a high-temperature heat exchanger.
The solution path may include a path for allowing a diluted solution flowing from the absorber to be branched and to flow to the high-temperature generator and the low-temperature generator, and a path for allowing the solution heated and concentrated in the high-temperature generator to flow from the high-temperature generator to the exhaust heat recovery generator.
Further, in order to achieve the second object, the high-temperature generator and the exhaust heat recovery generator are arranged along a straight line in a flow direction of the exhaust gas. The direction of the straight line is parallel to a longitudinal direction of the shell comprising the absorber, the evaporator, the condenser and the low-temperature generator, and hence it is possible to arrange an exhaust gas path in a compact manner (see FIGS. 13 and 14).
In order to achieve the first and second objects, according to a second aspect of the present invention, there is provided an absorption cold or hot water generating machine comprising: an absorber; a low-temperature generator; an exhaust heat recovery generator; a high-temperature generator; a condenser; an evaporator; a solution path and a refrigerant path for connecting the absorber, the low-temperature generator, the exhaust heat recovery generator, the high-temperature generator, the condenser, and the evaporator; and an exhaust gas path for introducing a high-temperature exhaust gas serving as a heat source into the high-temperature generator, and then the exhaust heat recovery generator; wherein the solution path includes a path for allowing a diluted solution flowing from the absorber to be branched and to flow to the high-temperature generator and the exhaust heat recovery generator, and a path for allowing the diluted solution heated and concentrated to an intermediate concentration by the high-temperature exhaust gas in the high-temperature generator to flow from the high-temperature generator to the low-temperature generator; and wherein the solution having the intermediate concentration led to the low-temperature generator is heated by refrigerant vapor generated in the high-temperature generator and serving as a heat source and is concentrated, and the diluted solution led to the exhaust heat recovery generator is heated and concentrated by the exhaust gas which has passed through the high-temperature generator.
The low-temperature generator may comprise a liquid film-type generator in which solution is sprayed on the heat transfer tube bank, and the refrigerant vapor generated in the exhaust heat recovery generator is led to the heat transfer tube bank of the low-temperature generator.
The absorption cold or hot water generating machine may further comprise a combustion device provided in the exhaust gas path for allowing the high-temperature exhaust gas to pass therethrough, and the combustion device is adapted to combust fuel supplied from the outside.
Because the exhaust heat recovery generator is provided to perform heat recovery further from the exhaust gas from which heat recovery has been performed in the high-temperature generator, the capacity of the cold or hot water generating machine can be increased. Because the high-temperature generator and the exhaust heat recovery generator which utilize the same heat source (exhaust gas) are connected in series in the exhaust gas path, the exhaust gas duct whose extension is difficult due to large specific volume can be prevented from being extended in a complicated manner. Thus, the overall structure of the apparatus can be compact.
The connection of the absorption solution piping employs such a flow that absorption solution flows smoothly in accordance with the pressure of the cycle. Specifically, the absorption solution flows from the high-temperature generator having a high pressure to the low-temperature generator, and then the absorber having a low pressure, thus performing double effect.
In order to utilize the quantity of heat of the exhaust gas as much as possible as a heat source of the exhaust heat recovery generator for thereby increasing thermal efficiency, it is necessary to lower the temperature of the exhaust gas at the outlet of the exhaust heat recovery generator. In the present invention, the absorption solution having a low concentration is introduced into the exhaust heat recovery generator to lower a boiling temperature of the solution. With this arrangement, the temperature of the exhaust gas at the outlet can be lowered and the quantity of heat of the exhaust gas obtained in the exhaust heat recovery generator can be increased.
The refrigerant vapor generated in the exhaust heat recovery generator is led to the vapor phase side of the low-temperature generator having a lower pressure, and joins the refrigerant vapor having a low pressure and generated in the low-temperature generator, and then the combined refrigerant vapor is led to the condenser where the refrigerant vapor is condensed by heat exchange with cooling water. A single condenser may be sufficient.
Further, in order to increase heat transfer in the low-temperature generator for thereby reducing the amount of absorption solution to be reserved, a liquid film-type generator is employed and a head of the solution pump can be utilized to spray absorption solution on the heat transfer tube bank in the low-temperature generator.
In order to achieve the first and second objects, according to a third aspect of the present invention, there is provided an absorption cold or hot water generating machine comprising: an absorber; a low-temperature generator; an exhaust heat recovery generator; a high-temperature generator; a condenser; an evaporator; a solution path and a refrigerant path for connecting the absorber, the low-temperature generator, the exhaust heat recovery generator, the high-temperature generator, the condenser, and the evaporator; and an exhaust gas path for introducing a high-temperature exhaust gas serving as a heat source into the high-temperature generator, and then the exhaust heat recovery generator; wherein the solution path includes a path for allowing absorption solution flowing from the absorber to be branched and to flow to the low-temperature generator and the exhaust heat recovery generator via a low-temperature heat exchanger, and to the high-temperature generator via a high-temperature heat exchanger; and wherein the absorption solution led to the high-temperature generator is heated and concentrated by the high-temperature exhaust gas, the absorption solution led to the exhaust heat recovery generator is heated and concentrated by the exhaust gas which has passed through the high-temperature generator, and the absorption solution led to the low-temperature generator is heated and concentrated by refrigerant vapor generated in the high-temperature generator.
The low-temperature generator may comprise a liquid film-type generator in which solution is sprayed on the heat transfer tube bank, and refrigerant vapor generated in the exhaust heat recovery generator is led to the heat transfer tube bank of the low-temperature generator.
The absorption cold or hot water generating machine may further comprise a combustion device provided in the exhaust gas path for allowing the high-temperature exhaust gas to pass therethrough, and the combustion device is adapted to combust fuel supplied from the outside.
In the absorption cold or hot water generating machine, the high-temperature generator and the exhaust heat recovery generator which utilize the same heat source (exhaust gas) are connected in series in the exhaust gas path to construct an exhaust gas generator, and hence an extension of the exhaust gas duct can be simplified.
According to the present invention, absorption liquid is supplied separately to the high-temperature generator, the exhaust heat recovery generator and the low-temperature generator, and hence it is possible to solve the above problems.
Further, in order to increase heat transfer in the low-temperature generator for thereby reducing the amount of absorption solution to be reserved, a liquid film-type generator is greatly employed. In the absorption cold or hot water generating machine according to the present invention, a head of the solution pump can be utilized to spray absorption solution on the heat transfer tube bank in the low-temperature generator.
In order to increase the quantity of heat of the exhaust gas utilized as a heat source in the high-temperature generator for thereby increasing the thermal efficiency, it is necessary to lower the temperature in the high-temperature generator.
In the absorption cold or hot water generating machine according to the present invention, absorption solution having a low concentration is introduced into the low-temperature generator, and the condensation temperature of the refrigerant vapor supplied from the high-temperature generator is lowered, and hence the temperature in the high-temperature generator can be lowered.
In order to achieve the first and second objects, according to another aspect in the third aspect of the present invention, there is provided an absorption cold or hot water generating machine comprising: an absorber; a low-temperature generator; an exhaust heat recovery generator; a high-temperature generator; a condenser; an evaporator; a solution path and a refrigerant path for connecting the absorber, the low-temperature generator, the exhaust heat recovery generator, the high-temperature generator, the condenser, and the evaporator; and an exhaust gas path for introducing a high-temperature exhaust gas serving as a heat source into the high-temperature generator, and then the exhaust heat recovery generator; wherein the solution path includes a path for allowing absorption solution flowing from the absorber to be divided into three parts and to be led to the high-temperature generator, the exhaust heat recovery generator, and the low-temperature generator; and wherein the total flow rate of the absorption solution led to the high-temperature generator, the exhaust heat recovery generator, and the low-temperature generator is distributed such that 45 to 70% of the total flow rate of the absorption solution is distributed to the low-temperature generator, and the remaining absorption solution is distributed to the high-temperature generator and the exhaust heat recovery generator at a ratio determined by a temperature of the exhaust gas to be supplied thereto.
The remaining absorption solution may be distributed such that when the temperature of the exhaust gas to be supplied thereto is Tgas, the ratio of the absorption solution led to the high-temperature generator is
{Tgasxe2x88x92(150xcx9c185)}/{Tgasxe2x88x92(90xcx9c120)}
within 10 to 90% of the remaining absorption solution.
The exhaust gas flowing through the exhaust heat recovery generator and the absorption solution may be heated and concentrated by the exhaust gas flow in a countercurrent flow.
The exhaust gas flowing through the high-temperature generator and the absorption solution may be heated and concentrated by the exhaust gas flow in a countercurrent flow.
The absorption cold or hot water generating machine may further comprise a high-temperature generator for supplemental combustion.
In order to achieve the first and second objects, according to a fourth aspect of the present invention, there is provided an absorption cold and hot water generating machine comprising: an absorber; a low-temperature generator; an exhaust heat recovery generator; a high-temperature generator; a condenser; an evaporator; a solution path and a refrigerant path for connecting the absorber, the low-temperature generator, the exhaust heat recovery generator, the high-temperature generator, the condenser, and the evaporator; and an exhaust gas path for introducing a high-temperature exhaust gas serving as a heat source into the high-temperature generator, and then the exhaust heat recovery generator; wherein the solution path includes a path for allowing absorption solution flowing from the absorber to be branched and to flow to the high-temperature generator and the low-temperature generator; and wherein the absorption solution led to the high-temperature generator is heated and concentrated by the high-temperature exhaust gas, the heated and concentrated absorption solution is led to the exhaust heat recovery generator and is heated and concentrated by the exhaust gas which has passed through the high-temperature generator, and the absorption solution led to the low-temperature generator is heated and concentrated by refrigerant vapor generated in the high-temperature generator.
The low-temperature generator may comprise a liquid film-type generator in which solution is sprayed on the heat transfer tube bank, and the refrigerant vapor generated in the exhaust heat recovery generator is led to the heat transfer tube bank of the low-temperature generator.
The absorption cold or hot water generating machine may further comprise a combustion device provided in the exhaust gas path for allowing the high-temperature exhaust gas to pass therethrough, and the combustion device is adapted to combust fuel supplied from the outside. Further, a heat recovery device for recovering heat from the exhaust gas may be provide between the high-temperature generator and the exhaust heat recovery generator, and downstream of the exhaust heat recovery generator in the heating path (exhaust gas path) for allowing the high-temperature exhaust gas to pass therethrough.
In order to achieve the first and second objects, according to a fifth aspect of the present invention, there is provided an absorption cold or hot water generating machine comprising: an absorber; a low-temperature generator; an exhaust heat recovery generator; a high-temperature generator; a condenser; an evaporator; a solution path and a refrigerant path for connecting the absorber, the low-temperature generator, the exhaust heat recovery generator, the high-temperature generator, the condenser, and the evaporator; and an exhaust gas path for introducing a high-temperature exhaust gas serving as a heat source into the high-temperature generator, and then the exhaust heat recovery generator; wherein the high-temperature generator and the exhaust heat recovery generator are connected along a substantially straight line in a flow direction of the exhaust gas, and the flow direction of the exhaust gas is parallel to a longitudinal direction of a shell comprising the absorber, the evaporator, the condenser, and the low-temperature generator.
The low-temperature generator may comprise a liquid film-type generator in which solution is sprayed on a heat transfer tube bank, and the refrigerant vapor generated in the exhaust heat recovery generator is led to the heat transfer tube bank of the low-temperature generator.
The absorption cold or hot water generating machine may further comprise a combustion device provided in the exhaust gas path for combusting fuel supplied from the outside. The combustion device may comprise a burner.
The absorption solution heated and concentrated by the refrigerant vapor supplied from the high-temperature generator in the low-temperature generator may be led to the exhaust heat recovery generator.
The solution path may include a path for allowing a diluted solution flowing from the absorber to be branched and to flow to the high-temperature generator and the exhaust heat recovery generator, and a path for allowing the solution heated and concentrated in the high-temperature generator to flow from the high-temperature generator to the low-temperature generator.
The solution path may include a path for allowing a diluted solution flowing from the absorber to be branched and to flow to the low-temperature generator and the exhaust heat recovery generator via a low-temperature heat exchanger, and to the high-temperature generator via a high-temperature heat exchanger.
The solution path may include a path for allowing a diluted solution flowing from the absorber to be branched and to flow to the high-temperature generator and the low-temperature generator, and a path for allowing the solution heated and concentrated in the high-temperature generator to flow from the high-temperature generator to the exhaust heat recovery generator.
The above and other objects, features, and advantages of the present invention will be apparent from the following description when taken in conjunction with the accompanying drawings which illustrates preferred embodiments of the present invention by way of example.